A target surface of a tape-shaped substrate of an oxide superconductor with an intermediate layer formed on this target surface and an oxide superconductor thin film is polished by causing the tape-shaped substrate to continuously run. The cantilever beam has a proximal end and an opposite distal end. A data frame is provided for communicating information between a first device and a second device attached to the network. An optical element with a saddle shaped structure is referred to as a saddle lens, and optical elements with different shaped saddle shaped structures provide different types of saddle lenses.